1. Field of the Invention This invention relates to mixers for mixing fibres into a slurry and particularly for mixing glass fibres into a relatively thick aqueous cement slurry, e.g. for use in forming glass fibre reinforced cement products on an asbestos-cement making machine of the Magnani type or, when appropriately diluted, on a machine of the Hatschek or Bell type.
2. Description of the Prior Art In such machines, an aqueous cement slurry, containing for example from 8 to 50% solids, is deposited on a foraminous surface and de-watered to form a sheet. In the Hatschek and Bell machines, after de-watering, successive sheets are deposited on an accumulator drum to build up a product of the desired thickness. When glass fibres are used instead of asbestos in such machines, difficulty has been experienced in mixing the glass fibres uniformly into the slurry. If a conventional paddletype mixing apparatus is used, the glass fibres have a tendency to clump together and to become unevenly distributed in the slurry and hence in the final product, which can thus fail to show the expected strength due to lack of reinforcement in some areas. Furthermore, the glass fibres can suffer mechanical damage from the mixing apparatus, which adversely affects their reinforcing effect in the composite material.